In these days, shortening of a time for mounting electronic components is increasingly required to improve productivity.
Hereinbelow, an example of a conventional electronic component mounting apparatus will be described with reference to the drawings. FIG. 12 schematically illustrates the whole constitution of a conventional mounting apparatus. In FIG. 12, 30 is an electronic component feed section for supplying an electronic component 31, and 32 is a board. 35 is a head section having two, i.e., a first and a second suction nozzles 12, 13 and a recognition camera 15, 33 is an X-axis table for moving the head section 35 in an X-axis direction, and 34 is a Y-axis table for moving the head section 35 in a Y-axis direction orthogonal to the X-axis direction which is a direction of the movement of the head section 35 by the X-axis table 33. The head section 35 is positioned at an optional position by the X-axis and Y-axis tables 33, 34. 100 is a main controller for the mounting apparatus and 104 is an operation panel of the apparatus.
In the conventional mounting apparatus of this type, the electronic component 31 in the component feed section 30 is mounted to the board 32 by the head section 35 in a single mounting procedure. That is, sucking of one component and mounting of one component are alternately carried out repeatedly.
The mounting procedure at the head section 35 is diagrammatically represented in FIGS. 3A-3J. FIG. 5 is a timing chart of the procedure. Portions shown by inclined lines in the timing chart from the "movement of the head section" to the "corrective rotation of the second nozzle" excluding the "recognition" process represents where the head section 35 is being driven, and portions shown by horizontal lines represent where the head section 35 is not driven. In the recognition process, upper straight parts are where the recognition process is executed, lower straight parts are where the recognition process is stopped and fine sawtoothed parts are where the recognition process is kept in a standby mode by a timer. After receiving a movement completion signal of a slide unit 14, a mirror in the slide unit 14 is vibrated consequent to the movement of the slide unit 14. The recognition process is not started until the vibration of the mirror is stopped, and the above standby time is provided for the mirror to stop vibrating. Referring to FIGS. 3A-3J, 12 is the first nozzle in the head section 35 and, 13 is the second nozzle also set in the head section 35 together with the first nozzle 12. 14 is the slide unit having a plurality of reflecting mirrors and set in the head section 35, and the slide unit 14 transmits a light image of the electronic component 31 sucked by the first or second nozzle 12, 13 to the recognition camera 15 of the head section 31 via the reflecting mirrors thereof. In the head section 35, the slide unit 14 moves in a horizontal direction between the first and second nozzles 12 and 13 to the recognition camera 15. The light image of the electronic component sucked by the first nozzle 12 is transmitted to the recognition camera 15 via the slide unit 14 at the side of the first nozzle 12. On the other hand, the light image of the electronic component sucked by the second nozzle 13 is transmitted to the recognition camera 15 via the slide unit 14 at the side of the second nozzle 13.
In the first place, the head section 35 is moved through the movement of the X-axis and Y-axis tables 33, 34 to a suction position 19 of the feed section 30 for suction by the first nozzle 12 (FIG. 3A). When the head section 35 is completely moved to the suction position 19 of the feed section 30, the first nozzle 12 descends, thereby sucking an electronic component 17 located at the suction position 19 (FIG. 3B). At this time, the second nozzle 13 is at a raised position and the slide unit 14 is set at the side of the second nozzle 13, so that the first nozzle 12 is allowed to move up and down. After the sucking of the electronic component 17 by the first nozzle 12 is completed, the first nozzle 12 moves upward and the head section 35 starts to move to a mounting position 20 of the board 32 for an electronic component 16 which has been sucked by the second nozzle 13 in a previous sucking operation (FIG. 3C). During the time when the head section 35 is moved to the suction position 19, the electronic component 17 is sucked by the first nozzle 12 and the head section 35 is moved to the mounting position 20, a sucked posture of the electronic component 16 by the second nozzle 13 is recognized by the recognition camera 15 via the slide unit 14, and the posture of the electronic component 16 relative to the head section 35 is corrected. As is well known, this correction is executed by minutely moving the second nozzle 13 to an optional position in the X-axis and Y-axis directions, or rotating the second nozzle 13 about its center axis. When the first nozzle 12 moves up completely, the slide unit 14 moves towards the first nozzle 12 (FIG. 3D). Upon completion of the movement of the slide unit 14 to the first nozzle 12 and of the head section 35 to the mounting position 20 of the board 32 for the electronic component 16 sucked by the second nozzle 13, the second nozzle 13 moves down to mount the sucked electronic component 16 to the mounting position 20 on the board 32 (FIG. 3E).
When the second nozzle 13 completes the mounting of the electronic component 16 to the board 32, the second nozzle 13 moves upward and the head section 35 starts to move to a suction position 21 over the feed section 30 for the next electronic component 18 to be sucked by the second nozzle 13 (FIG. 3F). When the head section 35 reaches the suction position 21 for the electronic component 18 to be sucked by the second nozzle 13, the second nozzle 13 moves down to suck the electronic component 18 at the suction position 21 (FIG. 3G). After the second nozzle 13 completely sucks the electronic component 18, the second nozzle 13 moves up and the head section 35 starts to move to a mounting position 22 of the board 32 for the electronic component 17 sucked by the first nozzle 12 (FIG. 3H). During this time while the head section 35 moves to the suction position 21, the second nozzle 13 sucks the electronic component 18 and the head section 35 moves to the mounting position 22, a posture of the electronic component 17 sucked by the first nozzle 12 is recognized by the recognition camera 15. The posture of the electronic component 17 relative to the head section 35 is corrected by minutely moving the first nozzle 12 to an optional position in the X- and Y-axes directions or rotating the first nozzle 12 about its central axis, as is well known. When the second nozzle 13 completely moves up, the slide unit 14 moves towards the second nozzle 13 (FIG. 3I). When the slide unit 14 comes to the side of the second nozzle 13 and the head section 35 completely moves to the mounting position 22 of the board 32 for the electronic component 17 sucked by the first nozzle 12, the first nozzle 12 moves down to mount the sucking electronic component 17 to the mounting position 22 of the board 32 (FIG. 3J). When completing the mounting of the electronic component 17, the first nozzle 12 moves up and the head section 35 starts to move to a suction position for the next electronic component 17 (FIG. 3A). This sequence of operations is repeated afterwards to sequentially mount electronic components.
According to the mounting procedure as above, the head section 35 reciprocates for each electronic component between the feed section 30 and the board 32. Therefore, a mounting time is easily adversely influenced by a distance between the suction position of the feed section 30 and the mounting position of the board 32. The mounting time is increased as the distance is increased. In other words, the above single mounting procedure generates a loss of time if adopted for a board having mounting points elongating the distance of the move of the head section 35. Since the mounting procedure includes unfavorable circumstances as above to increase the mounting time in each process, the single use of the mounting procedure accompanies a loss in mounting time per board.
The present invention has for its object to provide a method and an apparatus for mounting electronic components whereby a loss in mounting time caused by a single mounting procedure is reduced, to thereby shorten the mounting time per board.